October is Heartworm Prevention Month
Heartworm disease can be a very serious disease, and if untreated can be fatal.
Dogs can be infected with heartworms by a mosquito bite. Baby heartworms (microfilaria) live in the blood and migrate to the heart. Once they are in the heart, the set up camp and grow up to become adult heartworms. If the dog is infected with both male and female heartworms, the adults can make more baby heartworms. The next time the dog is bitten by a mosquito, the mosquito is infected with the heartworms and can go infect other dogs.
The initial mosquito bite and infection are not accompanied with any signs of disease (except maybe a little itching from the bite). If a dog is infected with heartworms, it can take months to years before he starts to show clinical signs of heartworm disease. The signs do not develop until the adult heartworm becomes large enough to cause heart problems. The worm blocks the vessels that take the blood away from the heart to the lungs. The can also get in the way of normal heart vessels.
Signs you may notice in dogs with heartworms are:
- Shortness of breath
- Loss of stamina
Once a dog is showing these signs of heartworm disease, treatment is necessary to kill the heartworms. However, this treatment can also be dangerous for a dog that is sick.
Okay, we know that the disease can be serious, but why bother testing if you are using a monthly preventative?
The term “heartworm prevention” is a bit misleading. The medication you give your dog once a month does not prevent them from getting bitten by the mosquito and getting infected with the microfilaria. The medication, if given appropriately, actually kills those microfilaria every month so they can not grow up and become adult heartworms.
Are you sure your dog is taking every pill you are giving him? If your dog takes the “treat” away and buries it, or vomits it up shortly after eating his pill, he will not be protected against heartworm. The medication needs to be in the body to work. Even missing just one month makes your dog more susceptible to becoming infected with heartworms.
Not all medications are 100% effective. If the dog is infected with a large number of microfilaria from multiple mosquito bites, the preventative medication may not be able to kill all the microfilaria, which could result in an infection.
What is the benefit of testing every year?
If the heartworm prevention does fail, or if you forget a dose, or if your dog doesn’t actually get the medication, annual heartworm testing can detect disease before your dog is showing clinical signs. If we can detect disease in the subclinical stage (before the dog looks sick) treatment of heartworm is much safer for your dog. The same medications are used to treat subclinical heartworm disease as are used to treat clinical (showing signs) heartworm disease. But if your dog still looks and feels healthy, the risk of your dog’s health is much less.
Testing is especially important if you do not use heartworm prevention year-round. Yes, there is a “mosquito season”. But that season changes every year. When we have mild winters, mosquitos season never really ends. If you wait to give prevention until you see the first mosquito of the season you have waited too long. It only takes one mosquito bite for your dog to be infected by microfilaria, and if you don’t start the preventative until two months after that, your dog is at very high risk for developing heartworm disease. Testing every two years can diagnose heartworm disease early. Early diagnosis means early treatment and a healthier dog!
What about cats?
Cats can also be infected with heartworms, although it is not as common as in dogs. Testing for heartworm disease in cats is not as easy as it is in dogs – the same tests won’t work in both dogs and cats, unfortunately. There are monthly heartworm preventatives available for cats. Ask about heartworm prevention for your cats at your next visit.
Once again this year Country Corners Veterinary Hospital will be offering out heartworm month special. If you bring your dog in for their yearly exam and purchase 12 months worth of prevention, we will perform the 4DX heartworm/tick borne disease test for free. This is a $41.50 value. Call to schedule early as these appointments fill up fast.
Dr. Sullivan and Staff at Country Corners Veterinary Hospital